This work should contribute to the understanding of periodontal disease by developing and testing antibodies to use for identifying parasite and host constituents of plaque that correlate with and probably participate in development of periodontal disease. In particular, it will provide immunochemical information about cell surface antigens which may act as virulence-associated factors for Actinomyces viscosus T14V. This organism is associated with plaque, root surface caries and immunological sensitization of periodontal patients and causes lesions in gnotobiotic rats.